From Semantic Web Technologies

RDF Formal Semantics

After having dealt with the RDF(S) language in the previous sections, we
now attend to its semantics. Our explanations closely follow the official W3C
RDF semantics specification document.

Before that, we will briefly explain why the definition of a formal semantics
became necessary (note that in the early days of RDF, there was no explicit,
mathematically defined semantics) and the advantages it brings about.